6 int readPaulicoeffs(int* alpha, int* beta, int* gamma, int* delta, int numqubits);
7 complex double Gausssum1d(int quadraticcoeff, int linearcoeff);
8 complex double Kroneck(int arg);
10 // order of matrix elements is [row][column]!!!
17 int N; // number of qubits
20 int alpha[N], beta[N], gamma[N], delta[N];
22 double complex summand, sum;
24 while(readPaulicoeffs(alpha, beta, gamma, delta, N)) {
27 // printf("%d %d %d %d\n", alpha[i], beta[i], gamma[i], delta[i]);
33 summand += 0.5*(Kroneck(gamma[i]+delta[i]) + pow(-1,beta[i])*Kroneck(gamma[i]+delta[i])
34 +csqrt(I)*cpow(-I,delta[i])*Kroneck(alpha[i]+beta[i]) + csqrt(-I)*cpow(I,delta[i])*Kroneck(alpha[i]+beta[i]));
37 //printf("%lf+%lfI\n", creal(sum), cimag(sum));
38 printf("%lf\n", cabs(creal(sum)));
46 complex double Kroneck(int arg)
48 arg = (arg+1)%2; // output 1 if argument is 0 mod 2 and 0 otherwise
49 return ((complex double)arg);
52 complex double Gausssum1d(int quadraticcoeff, int linearcoeff)
54 // we assume coeffs are either 0 or 1
58 if(quadraticcoeff == 0)
71 int readPaulicoeffs(int *alpha, int *beta, int *gamma, int *delta, int numqubits)
76 if(scanf("%d %d %d %d", &alpha[0], &beta[0], &gamma[0], &delta[0]) != EOF) {
77 for(i=1; i<numqubits; i++) {
78 scanf("%d %d %d %d", &alpha[i], &beta[i], &gamma[i], &delta[i]);